Signal acquisition circuit and device for insulation detection

Abstract

The utility model relates to a signal acquisition circuit and a signal acquisition device for insulation detection, which are used for improving the signal acquisition reliability of insulation monitoring. The circuit comprises a voltage dividing module and a filtering acquisition module. The voltage dividing module is composed of a positive insulation voltage dividing unit and a negative insulation voltage dividing unit, and the filtering acquisition module comprises a positive insulation acquisition unit and a negative insulation acquisition unit. The positive insulation voltage division unit receives a signal of a positive electrode of a power supply to be tested and performs voltage division, an obtained positive insulation signal to be acquired is input to the positive insulation acquisition unit for filtering processing, and finally a positive insulation differential signal is output to the signal processing circuit. Similarly, the negative insulation voltage division unit receives the signal of the negative electrode of the power supply to be tested and performs voltage division, the obtained negative insulation signal to be acquired is input to the negative insulation acquisition unit for filtering processing, and finally the negative insulation differential signal is output to the signal processing circuit. According to the invention, the accuracy and reliability of signal acquisition in the insulation monitoring process can be effectively improved.

Description

Technical Field

[0001] The present application relates to the technical field of insulation detection, and in particular to a signal acquisition circuit and device for insulation detection. Background Art

[0002] The insulation performance detection circuit plays a vital role in ensuring the safe and stable operation of the power system. Insulation performance refers to the ability to use insulating materials and components to separate conductors with unequal potentials so that they are not electrically connected to maintain different potentials, thereby ensuring that live parts can work normally. Insulation performance detection is an important means to ensure the safe operation of electrical equipment. By performing insulation resistance tests and insulation withstand voltage tests on the equipment, its insulation performance can be effectively evaluated, thereby preventing electrical accidents and ensuring the safety of people and equipment. In actual operation, appropriate test instruments should be selected, wiring should be performed correctly, operations should be performed as required, and safety precautions should be paid attention to to ensure the accuracy and reliability of the test. The detection accuracy of insulation performance is crucial, which is not only related to the safety and stability of the power system, but also involves equipment reliability, user experience, technological innovation, and economic and environmental factors.

[0003] It can be seen that improving the accuracy of insulation performance testing is the key to ensuring the safe and efficient operation of the power system. The accuracy of insulation performance testing is inseparable from the reliability of signal acquisition during insulation testing. Therefore, how to improve the reliability of signal acquisition for insulation monitoring is a technical problem that needs to be solved urgently. Utility Model Content

[0004] The embodiments of the present application provide a signal acquisition circuit and device for insulation detection, which can achieve the beneficial effect of improving the reliability of signal acquisition for insulation monitoring.

[0005] In a first aspect, the present application provides a signal acquisition circuit for insulation detection: comprising a voltage division module and a filtering acquisition module;

[0006] The voltage division module includes a positive insulation voltage division unit and a negative insulation voltage division unit, and the filtering collection module includes a positive insulation collection unit and a negative insulation collection unit;

[0007] The input end of the positive insulation voltage divider unit is connected to the positive electrode of the power supply to be tested, and the output end of the positive insulation voltage divider unit is connected to the input end of the positive insulation acquisition unit, and is used to divide the positive signal sent by the positive electrode through the positive insulation voltage divider unit to obtain the positive insulation signal to be collected which is input to the positive insulation acquisition unit;

[0008] The input end of the positive insulation acquisition unit is connected to a group of input ends of an external signal processing circuit, and is used to filter the positive insulation signal to be collected to obtain a positive insulation differential signal, and output the positive insulation differential signal to the signal processing circuit after filtering;

[0009] The input end of the negative insulation voltage dividing unit is connected to the negative pole of the power supply under test, and the output end of the negative insulation voltage dividing unit is connected to the input end of the negative insulation acquisition unit, which is used to divide the negative signal sent by the negative pole through the negative insulation voltage dividing unit to obtain a negative insulation signal to be acquired input to the negative insulation acquisition unit;

[0010] The output end of the negative insulation acquisition unit is connected to another group of input ends of the signal processing circuit, which is used to filter the negative insulation signal to be acquired to obtain a negative insulation differential signal, and output the filtered negative insulation differential signal to the signal processing circuit.

[0011] By adopting the above technical solution, the positive insulation detection receives the positive input, divides the voltage through the positive insulation voltage dividing unit, and then obtains the positive insulation differential signal through one of the resistors in the positive insulation acquisition unit. The positive insulation differential signal is then output to the external signal processing circuit through the low-pass filter formed by the resistor and capacitor, thereby completing the acquisition of the positive insulation signal. The interference signal can be effectively removed through the low-pass filter; similarly, the negative insulation receives the negative input, divides the voltage through the negative insulation voltage dividing unit, and then obtains a negative insulation differential signal in the negative insulation acquisition unit. The negative insulation differential signal is output to the signal processing circuit after passing through the low-pass filter of the resistor-capacitor RC to improve the acquisition reliability of the negative insulation differential signal.

[0012] Optionally, the positive insulation voltage dividing unit includes a first resistor, a second resistor, a third resistor, a first capacitor, a second capacitor, and a third capacitor;

[0013] One end of the first resistor is connected to the output end of the positive insulation voltage dividing unit and one end of the second resistor, and the other end of the first resistor is connected to the reference point and one end of the third resistor;

[0014] The other end of the second resistor is connected to one end of the first capacitor, one end of the second capacitor, and one of the input ends of a group of input ends of the signal processing circuit, and the other end of the first capacitor is grounded;

[0015] One end of the third resistor is connected to one end of the third capacitor, the other end of the second capacitor, and the other input end of a group of input ends of the signal processing circuit, and the other end of the third capacitor is grounded.

[0016] By adopting the above technical solution, the input signal (positive signal) in the positive insulation acquisition unit passes through the first resistor to the reference ground to initially obtain a positive insulation differential signal. This positive insulation differential signal is output to one input terminal of the signal processing circuit through the low-pass filter formed by the second resistor and the first capacitor, and is also output to the other input terminal of the signal processing circuit through the low-pass filter formed by the third resistor and the third capacitor, thereby acquiring different voltage differences, and then different insulation resistance values can be calculated to achieve positive insulation detection.

[0017] Optionally, the negative insulation voltage division unit includes a fourth resistor, a fifth resistor, a sixth resistor, a fourth capacitor, a fifth capacitor, and a sixth capacitor;

[0018] One end of the fourth resistor is connected to the output terminal of the negative insulation voltage division unit and one end of the fifth resistor, and the other end of the fourth resistor is connected to the reference point and one end of the sixth resistor;

[0019] The other end of the fifth resistor is connected to one end of the fourth capacitor, one end of the fifth capacitor, and one input terminal of another group of input terminals of the signal processing circuit, and the other end of the fourth capacitor is grounded;

[0020] One end of the sixth resistor is connected to one end of the sixth capacitor, the other end of the fifth capacitor, and the other input terminal of another group of input terminals of the signal processing circuit, and the other end of the sixth capacitor is grounded.

[0021] By adopting the above technical solution, the input signal (negative signal) in the negative insulation acquisition unit passes through the fourth resistor to the reference ground to initially obtain a negative insulation differential signal. This negative insulation differential signal is output to one input terminal of the signal processing circuit through the low-pass filter formed by the fifth resistor and the fourth capacitor, and is also output to the other input terminal of the signal processing circuit through the low-pass filter formed by the sixth resistor and the sixth capacitor, thereby acquiring different voltage differences, and then different insulation resistance values can be calculated to achieve negative insulation detection.

[0022] Optionally, the positive insulation voltage division unit includes a first resistor string, and the first resistor string is composed of a plurality of resistors connected in series;

[0023] One end of the first resistor string is connected to the positive electrode, and the other end is connected to the connection point between the first resistor and the second resistor.

[0024] Optionally, the negative insulation voltage division unit includes a second resistor string, and the second resistor string is composed of a plurality of resistors connected in series;

[0025] One end of the second resistor string is connected to the negative electrode, and the other end is connected to the connection point between the fourth resistor and the fifth resistor.

[0026] By adopting the above technical solution, when the positive power supply terminal (BAT+) is connected, voltage division is performed through the first resistor string, and the voltage-divided signal is input to the positive insulation acquisition unit. When the negative power supply terminal (BAT-) is connected, voltage division is performed through the second resistor string, and the voltage-divided signal is input to the negative insulation acquisition unit.

[0027] Optionally, it further includes a voltage division adjustment module. The voltage division adjustment module includes a first optocoupler, a seventh resistor, and an eighth resistor. The first optocoupler includes eight ports;

[0028] The first port of the first optocoupler is connected to one end of the seventh resistor and the other end of the first resistor string, and the other end of the seventh resistor is connected to the second port of the first optocoupler;

[0029] The third port of the first optocoupler is connected to one end of the eighth resistor and the other end of the second resistor string, and the other end of the eighth resistor is connected to the fourth port of the first optocoupler;

[0030] The fifth port and the sixth port of the first optocoupler are used to receive signals sent by an external control circuit and correspondingly control the on-off between the first port and the second port of the first optocoupler;

[0031] The seventh port and the eighth port of the first optocoupler are used to receive signals sent by the control circuit and correspondingly control the on-off between the third port and the fourth port of the first optocoupler.

[0032] By adopting the above technical solution, the fifth port and the sixth port of the first optocoupler are used to receive external control signals and correspondingly turn on the triode between its first port and second port. After turning on, at least one resistor in the first resistor string is short-circuited, thereby forming two different resistance values for voltage division. Similarly, the seventh port and the eighth port are used to receive external control signals and correspondingly turn on the triode between the third port and the fourth port, thereby short-circuiting at least one resistor in the second resistor string and forming two different resistance values for voltage division in the negative insulation detection part.

[0033] Optionally, the positive insulation voltage division unit further includes a second optocoupler, and the negative insulation voltage division unit further includes a third optocoupler;

[0034] The first port of the second optocoupler is connected to the connection point between the first resistor string and the positive electrode, the second port of the second optocoupler is connected to the first port of the third optocoupler, and the second port of the third optocoupler is connected to the connection point between the second resistor string and the negative electrode;

[0035] The third port and the fourth port of the second optocoupler are used to receive the signals sent by the control circuit, and correspondingly control the on-off between the first port and the second port of the second optocoupler;

[0036] The third port and the fourth port of the third optocoupler are used to receive the signals sent by the control circuit, and correspondingly control the on-off between the first port and the second port of the third optocoupler.

[0037] By adopting the above technical solution, the second optocoupler and the third optocoupler receive external control signals, and are connected to the positive power supply terminal (BAT+) and the negative power supply terminal (BAT-) through optocoupler isolation, so as to avoid damaging the control circuit for sending control signals due to high voltage.

[0038] The second aspect of the present application provides a signal acquisition device for insulation detection, which is equipped with the above-mentioned signal acquisition circuit for insulation detection.

[0039] In summary, the beneficial effects of the present application are as follows: The positive insulation detection receives the positive input, divides the voltage through the positive insulation voltage division unit, and then to the positive insulation acquisition unit to obtain the positive insulation differential signal through one of the resistors. The positive insulation differential signal then passes through the low-pass filter formed by the resistor and capacitor and is output to the external signal processing circuit, thereby completing the acquisition of the positive insulation signal. The interference signal can be effectively removed through the low-pass filter; similarly, the negative insulation receives the negative input, divides the voltage through the negative insulation voltage division unit, and then to the negative insulation acquisition unit to obtain a negative insulation differential signal. The negative insulation differential signal is output to the signal processing circuit after passing through the low-pass filter of the resistor-capacitor RC to improve the acquisition reliability of the negative insulation differential signal. Description of the Drawings

[0040] Figure 1 is a schematic diagram of the modules of the signal acquisition circuit for insulation detection provided by the embodiment of the present application;

[0041] Figure 2 is the circuit schematic diagram of the signal acquisition circuit for insulation detection provided by the embodiment of the present application;

[0042] Figure 3 is the circuit schematic diagram of the filter acquisition module 2 in the signal acquisition circuit for insulation detection provided by the embodiment of the present application. Detailed Embodiments

[0043] The following embodiments will help those skilled in the art to further understand the functions of the present application, but do not limit the present application in any form. It should be noted that those of ordinary skill in the art can make several deformations and improvements without departing from the concept of the present application. These all belong to the protection scope of the present application.

[0044] In the following description, specific details such as specific system architectures, technologies, etc. are presented for purposes of illustration and not limitation, so as to provide a thorough understanding of the embodiments of the present application. However, those skilled in the art should understand that the present application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from obscuring the description of the present application.

[0045] It should be understood that when used in the specification and appended claims of the present application, the term "comprising" indicates the presence of the described features, wholes, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0046] It should also be understood that the term "and / or" as used in the specification and appended claims of the present application refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0047] In addition, in the description of the specification and appended claims of the present application, the terms "first", "second", "third", etc. are only used for differentiating descriptions and should not be construed as indicating or implying relative importance.

[0048] The reference to "one embodiment" or "some embodiments" etc. described in the specification of the present application means that a specific feature, structure, or characteristic described in connection with that embodiment is included in one or more embodiments of the present application. Thus, statements such as "in one embodiment", "in some embodiments", "in other some embodiments", "in still other embodiments", etc. that appear in different places in this specification do not necessarily all refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in another way. The terms "comprising", "including", "having", and their variants all mean "including but not limited to", unless otherwise specifically emphasized in another way.

[0049] The present application will be further described in detail below with reference to the accompanying drawings.

[0050] Refer to Figure 1, which is a schematic diagram of the module of the signal acquisition circuit for insulation detection provided by the embodiment of the present application. It includes a voltage division module 1 and a filtering and acquisition module 2. Among them, the voltage division module 1 includes a positive insulation voltage division unit and a negative insulation voltage division unit, and the filtering and acquisition module 2 includes a positive insulation acquisition unit and a negative insulation acquisition unit. In addition, it also includes an external control circuit for controlling the access of the signal source, a voltage division adjustment module for adjusting the voltage division resistance value of the voltage division module 1, and a signal processing circuit for receiving and processing the acquired insulation signals. This design includes the acquisition of positive insulation signals and negative insulation signals. The following will first specifically describe the acquisition of positive insulation signals:

[0051] The input end of the positive insulation voltage division unit is connected to the positive pole BAT+ of the power supply to be measured, and the output end of the positive insulation voltage division unit is connected to the input end of the positive insulation acquisition unit, which is used to divide the positive pole BAT+ signal sent by the positive pole BAT+ through the positive insulation voltage division unit to obtain a positive insulation signal to be acquired input to the positive insulation acquisition unit;

[0052] The input end of the positive insulation acquisition unit is connected to a group of input ends of an external signal processing circuit, which is used to filter the positive insulation signal to be acquired to obtain a positive insulation differential signal, and output the filtered positive insulation differential signal to the signal processing circuit.

[0053] Specifically, the positive insulation voltage division unit divides the signal sent by the positive pole BAT+ of the signal source, and then the positive insulation acquisition unit obtains a positive insulation differential signal through one of the resistors. The positive insulation differential signal then passes through a low-pass filter formed by a resistor and a capacitor and is output to an external signal processing circuit, thereby completing the acquisition of the positive insulation signal. The interference signals can be effectively removed through the low-pass filter. The signal processing circuit can include an ADC chip and an isolation chip. The positive insulation signal is input to the ADC chip, and different insulation resistance values are obtained through different voltage difference calculations. After passing through IC communication to the isolation chip and then to the single-chip microcomputer for calculation and processing, the positive insulation detection is realized.

[0054] Similar to the positive insulation detection principle, the following will specifically describe the process of negative insulation detection:

[0055] The input end of the negative insulation voltage division unit is connected to the negative pole BAT- of the power supply to be measured, and the output end of the negative insulation voltage division unit is connected to the input end of the negative insulation acquisition unit, which is used to divide the negative pole BAT- signal sent by the negative pole BAT- through the negative insulation voltage division unit to obtain a negative insulation signal to be acquired input to the negative insulation acquisition unit;

[0056] The output end of the negative insulation acquisition unit is connected to another set of input ends of the signal processing circuit, and is used to filter the negative insulation signal to be acquired to obtain a negative insulation differential signal, and output the filtered negative insulation differential signal to the signal processing circuit.

[0057] Specifically, the negative insulation receives the input of the negative pole BAT-, is divided by the negative insulation voltage dividing unit, and then reaches the negative insulation acquisition unit to obtain a negative insulation differential signal. The negative insulation differential signal is output to the signal processing circuit after low-pass filtering by a resistor-capacitor RC to improve the acquisition reliability of the negative insulation differential signal. Please refer to the following Figure 2 , Figure 2 FIG. is the circuit schematic diagram of the filtering and acquisition module 2 in the signal acquisition circuit for insulation detection provided by the embodiment of the present application, including a positive insulation acquisition unit and a negative insulation acquisition unit, and the following is a specific description:

[0058] The positive insulation voltage dividing unit includes a first resistor R1, a second resistor R2, a third resistor R3, a first capacitor C1, a second capacitor C2, and a third capacitor C3;

[0059] One end of the first resistor R1 is connected to the output end of the positive insulation voltage dividing unit and one end of the second resistor R2, and the other end of the first resistor R1 is connected to the reference point and one end of the third resistor R3;

[0060] The other end of the second resistor R2 is connected to one end of the first capacitor C1, one end of the second capacitor C2, and one of the input ends of a set of input ends of the signal processing circuit, and the other end of the first capacitor C1 is grounded;

[0061] One end of the third resistor R3 is connected to one end of the third capacitor C3, the other end of the second capacitor C2, and the other input end of a set of input ends of the signal processing circuit, and the other end of the third capacitor C3 is grounded.

[0062] Specifically, the input signal (positive pole BAT+ signal) in the positive insulation acquisition unit passes through the first resistor R1 to the reference ground to initially obtain a positive insulation differential signal. This positive insulation differential signal is output to one input end of the signal processing circuit through the low-pass filter formed by the second resistor R2 and the first capacitor C1, and is also output to the other input end of the signal processing circuit through the low-pass filter formed by the third resistor R3 and the third capacitor C3, so as to acquire different voltage differences, and then different insulation resistance values can be calculated to achieve positive insulation detection.

[0063] The negative insulation voltage dividing unit includes a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a fourth capacitor C4, a fifth capacitor C5, and a sixth capacitor C6;

[0064] One end of the fourth resistor R4 is connected to the output end of the negative insulation voltage dividing unit and one end of the fifth resistor R5, and the other end of the fourth resistor R4 is connected to the reference point and one end of the sixth resistor R6;

[0065] The other end of the fifth resistor R5 is connected to one end of the fourth capacitor C4, one end of the fifth capacitor C5, and one input end of another group of input ends of the signal processing circuit, and the other end of the fourth capacitor C4 is grounded;

[0066] One end of the sixth resistor R6 is connected to one end of the sixth capacitor C6, the other end of the fifth capacitor C5, and the other input end of another group of input ends of the signal processing circuit, and the other end of the sixth capacitor C6 is grounded.

[0067] Specifically, similar to the above positive insulation acquisition unit, in the negative insulation acquisition unit, the input signal (negative pole BAT- signal) passes through the fourth resistor R4 to the reference ground to initially obtain a negative insulation differential signal. This negative insulation differential signal is output to one input end of the signal processing circuit through the low-pass filter formed by the fifth resistor R5 and the fourth capacitor C4, and is also output to the other input end of the signal processing circuit through the low-pass filter formed by the sixth resistor R6 and the sixth capacitor C6, so as to collect different voltage differences, and then different insulation resistance values can be calculated to achieve negative insulation detection.

[0068] Please refer to the following Figure 3 , Figure 3 which is the circuit schematic diagram of the filtering and acquisition module 2 in the signal acquisition circuit for insulation detection provided by the embodiment of the present application, including a positive insulation voltage dividing unit, a negative insulation voltage dividing unit, and a voltage dividing adjustment module for adjusting the resistance values of these two voltage dividing units. The following will be specifically described:

[0069] The positive insulation voltage dividing unit includes a first resistor string R11, and the first resistor string R11 is composed of a plurality of resistors connected in series;

[0070] One end of the first resistor string R11 is connected to the positive pole BAT+, and the other end is connected to the connection point of the first resistor R1 and the second resistor R2.

[0071] The negative insulation voltage dividing unit includes a second resistor string R12, and the second resistor string R12 is composed of a plurality of resistors connected in series;

[0072] One end of the second resistor string R12 is connected to the negative pole BAT-, and the other end is connected to the connection point of the fourth resistor R4 and the fifth resistor R5.

[0073] Specifically, when the positive power supply terminal BAT+ (BAT+) is connected, it is divided by the first resistor string R11, and the divided signal is input to the positive insulation acquisition unit, that is, input to the Figure 2 HIGH_R0_0 port in the above, when the negative power supply terminal BAT- (BAT-) is connected, it is divided by the second resistor string R12, and the divided signal is input to the negative insulation acquisition unit, that is, input to the Figure 2 LOW_R0_0 in the above.

[0074] More specifically, the on / off of the voltage division adjustment module can be used to correspondingly adjust the resistance values of the positive and negative insulation voltage division units. The specific description is as follows:

[0075] The voltage division adjustment module includes a first optocoupler, a seventh resistor R7, and an eighth resistor R8. The first optocoupler includes eight ports;

[0076] The first port of the first optocoupler is connected to one end of the seventh resistor R7 and the other end of the first resistor string R1, and the other end of the seventh resistor R7 is connected to the second port of the first optocoupler;

[0077] The third port of the first optocoupler is connected to one end of the eighth resistor R8 and the other end of the second resistor string R2, and the other end of the eighth resistor R8 is connected to the fourth port of the first optocoupler;

[0078] The fifth and sixth ports of the first optocoupler are used to receive signals sent by an external control circuit and correspondingly control the on / off between the first and second ports of the first optocoupler;

[0079] The seventh and eighth ports of the first optocoupler are used to receive signals sent by the control circuit and correspondingly control the on / off between the third and fourth ports of the first optocoupler.

[0080] Specifically, the fifth and sixth ports of the first optocoupler are used to receive external control signals and correspondingly conduct the triode between its first and second ports. After conduction, at least one resistor in the first resistor string R11 is short-circuited, thereby forming two different resistance values for voltage division; similarly, the seventh and eighth ports are used to receive external control signals and correspondingly conduct the triode between the third and fourth ports, thereby short-circuiting at least one resistor in the second resistor string R12 and forming two different resistance values for voltage division in the negative insulation detection part. In this embodiment, when the triode between the first and second ports of the first optocoupler is conducted, the seventh resistor R7 is short-circuited. Otherwise, the seventh resistor R7 is also counted into the first resistor string R11, thereby realizing two different voltage division resistance values; the situation of the eighth resistor R8 is similar and is used to adjust the resistance value of the second resistor string R12, which will not be elaborated here.

[0081] More specifically, to ensure the reliability of the circuit, high-voltage isolation can also be achieved through isolation, which is specifically described below:

[0082] The positive insulation voltage division unit further includes a second optocoupler, and the negative insulation voltage division unit further includes a third optocoupler;

[0083] The first port of the second optocoupler is connected to the connection point of the first resistor string R11 and the positive electrode BAT+; the second port of the second optocoupler is connected to the first port of the third optocoupler; the second port of the third optocoupler is connected to the connection point of the second resistor string R12 and the negative electrode BAT-.

[0084] The third port and the fourth port of the second optocoupler are used to receive the signal sent by the control circuit and correspondingly control the on / off between the first port and the second port of the second optocoupler;

[0085] The third port and the fourth port of the third optocoupler are used to receive the signal sent by the control circuit and correspondingly control the on / off between the first port and the second port of the third optocoupler.

[0086] Specifically, the second optocoupler and the third optocoupler receive external control signals, and are optically isolated and connected to the power supply positive electrode BAT+ (BAT+) and the power supply negative electrode BAT- (BAT-), so as to avoid high voltage from damaging the control circuit for sending control signals.

[0087] Taking the positive insulation detection part as an example, when the second optocoupler is turned on through an external control level, the positive electrode BAT+ is connected to the resistor string in the positive insulation voltage division unit for voltage division, and then a differential voltage (positive insulation differential voltage) is obtained through the first resistor R1 to the reference ground. This differential voltage is low-pass filtered through the second resistor R2 and output to HIGH_INSULATION_AIN0, and low-pass filtered through the third resistor R3 and output to HIGH_INSULATION_AIN1 to the ADC chip, and the corresponding insulation resistance value is obtained through different voltage difference calculations.

[0088] Similarly, the working principle of the negative insulation detection part is: when the third optocoupler is turned on through an external control level, the negative electrode BAT- is connected to the resistor string in the negative insulation voltage division unit for voltage division, and then a differential voltage (negative insulation differential voltage) is obtained through the fourth resistor R4 to the reference ground. This differential voltage is low-pass filtered through the fifth resistor R5 and output to HIGH_INSULATION_AIN2, and low-pass filtered through the sixth resistor R6 and output to HIGH_INSULATION_AIN3 to the ADC chip, and the corresponding insulation resistance value is obtained through different voltage difference calculations.

[0089] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A signal acquisition circuit for insulation detection, characterized in that: It includes a voltage divider module and a filter acquisition module; The voltage division module includes a positive insulation voltage division unit and a negative insulation voltage division unit, and the filtering collection module includes a positive insulation collection unit and a negative insulation collection unit; The input end of the positive insulation voltage divider unit is connected to the positive electrode of the power supply to be tested, and the output end of the positive insulation voltage divider unit is connected to the input end of the positive insulation acquisition unit, and is used to divide the positive signal sent by the positive electrode through the positive insulation voltage divider unit to obtain the positive insulation signal to be collected which is input to the positive insulation acquisition unit; The input end of the positive insulation acquisition unit is connected to a group of input ends of an external signal processing circuit, and is used to filter the positive insulation signal to be collected to obtain a positive insulation differential signal, and output the positive insulation differential signal to the signal processing circuit after filtering; The input end of the negative insulation voltage divider unit is connected to the negative electrode of the power supply to be tested, and the output end of the negative insulation voltage divider unit is connected to the input end of the negative insulation acquisition unit, and is used to divide the negative electrode signal sent by the negative electrode through the negative insulation voltage divider unit to obtain the negative insulation signal to be collected which is input to the negative insulation acquisition unit; The output end of the negative insulation acquisition unit is connected to another group of input ends of the signal processing circuit, which is used to filter the negative insulation signal to be collected to obtain a negative insulation differential signal, and output the negative insulation differential signal to the signal processing circuit after filtering.

2. The signal acquisition circuit for insulation detection according to claim 1 is characterized in that: The positive insulating voltage dividing unit comprises a first resistor, a second resistor, a third resistor, a first capacitor, a second capacitor and a third capacitor; One end of the first resistor is connected to the output end of the positive insulating voltage dividing unit and one end of the second resistor, and the other end of the first resistor is connected to a reference point and one end of the third resistor; The other end of the second resistor is connected to one end of the first capacitor, one end of the second capacitor and one input end of a group of input ends of the signal processing circuit, and the other end of the first capacitor is grounded; One end of the third resistor is connected to one end of the third capacitor, the other end of the second capacitor, and another input end of a set of input ends of the signal processing circuit, and the other end of the third capacitor is grounded.

3. The signal acquisition circuit for insulation detection according to claim 2 is characterized in that: The negative insulation voltage dividing unit includes a fourth resistor, a fifth resistor, a sixth resistor, a fourth capacitor, a fifth capacitor and a sixth capacitor; One end of the fourth resistor is connected to the output end of the negative insulation voltage dividing unit and one end of the fifth resistor, and the other end of the fourth resistor is connected to the reference point and one end of the sixth resistor; The other end of the fifth resistor is connected to one end of the fourth capacitor, one end of the fifth capacitor and one input end of another group of input ends of the signal processing circuit, and the other end of the fourth capacitor is grounded; One end of the sixth resistor is connected to one end of the sixth capacitor, the other end of the fifth capacitor, and another input end of the other input end group of the signal processing circuit, and the other end of the sixth capacitor is grounded.

4. The signal acquisition circuit for insulation detection according to claim 3 is characterized in that: The positive insulation voltage dividing unit comprises a first resistor string, wherein the first resistor string is composed of a plurality of resistors connected in series; One end of the first resistor string is connected to the positive electrode, and the other end is connected to the connection point between the first resistor and the second resistor.

5. The signal acquisition circuit for insulation detection according to claim 4 is characterized in that: The negative insulation voltage dividing unit comprises a second resistor string, wherein the second resistor string is composed of a plurality of resistors connected in series; One end of the second resistor string is connected to the negative electrode, and the other end is connected to the connection point between the fourth resistor and the fifth resistor.

6. The signal acquisition circuit for insulation detection according to claim 5, characterized in that: Also includes a voltage division adjustment module, the voltage division adjustment module includes a first optical coupler, a seventh resistor and an eighth resistor, the first optical coupler includes eight ports; The first port of the first optical coupler is connected to one end of the seventh resistor and the other end of the first resistor string, and the other end of the seventh resistor is connected to the second port of the first optical coupler; The third port of the first optical coupler is connected to one end of the eighth resistor and the other end of the second resistor string, and the other end of the eighth resistor is connected to the fourth port of the first optical coupler; The fifth port and the sixth port of the first optical coupler are used to receive a signal sent by an external control circuit, and correspondingly control the on-off between the first port and the second port of the first optical coupler; The seventh port and the eighth port of the first optical coupler are used to receive the signal sent by the control circuit, and correspondingly control the on-off between the third port and the fourth port of the first optical coupler.

7. The signal acquisition circuit for insulation detection according to claim 6, characterized in that: The positive insulation voltage-dividing unit further includes a second optical coupler, and the negative insulation voltage-dividing unit further includes a third optical coupler; The first port of the second optical coupler is connected to the connection point between the first resistor string and the positive electrode, the second port of the second optical coupler is connected to the first port of the third optical coupler, and the second port of the third optical coupler is connected to the connection point between the second resistor string and the negative electrode; The third port and the fourth port of the second optical coupler are used to receive the signal sent by the control circuit, and correspondingly control the on-off between the first port and the second port of the second optical coupler; The third port and the fourth port of the third optical coupler are used to receive the signal sent by the control circuit, and correspondingly control the connection and disconnection between the first port and the second port of the third optical coupler.

8. A signal acquisition device for insulation detection, characterized in that: The device is equipped with a signal acquisition circuit for insulation detection as described in any one of claims 1 to 7.

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